In swimming pools, the water need to be regularly filtered and cleaned from marcroparticles as well as micro-organisms. Macroparticles are removed from the water by a recirculating water duct network, coupled to the swimming pool walls Micro-organisms, including fungi, yeast, algae, bacteria and others, are attacked mainly by chemical agents poured at periodic intervals into the swimming pool water.
By definition, a large body of stagnating water constitutes an anaerobic milieu, i.e. that it contains a very low if any concentration of dissolved oxygen (from the air). Accordingly, only anaerobic micro-organisms will usually survive into such large bodies of stagnating water. The chemical agents used in swimming pools as bactericidal agents are accordingly directed toward these anaerobic organisms.
Unfortunately, the action of such chemical agents is not always thorough, as they will tend to fall to the bottom of the swimming pool after a while. Moreover, these chemical agents (e.g. chlorine based) have irritating or damaging effects on the tissues of bathers, particularly for the skin and cornea. These chemical agents are also damaging to the environment and for this reason, are not considered to be ecologically sound. In addition, chemical bactericidal agents are very expensive and, since they must be used in substantial quantities at regular intervals in the large body of water enclosed in the swimming pool basin, they constitute a recurrent and important variable cost for the owner of the swimming pool. Alternate means must therefore be devised to at least complement the conventional agents that skill these micro-organisms responsive for foul odors, non-aesthetic coloration of the swimming pool water, eventual build-up of unappealing colonies of such organisms, and possibly transmission of disease to bathers.
This is one reason why water oxygenation is found useful. By increasing the ratio of dissolved air in the water, the mainly anaerobic micro-organisms living in the swimming pool water can no longer grow, since oxygen is lethal for them. In some water recirculation systems, this water oxygenation occurs about the conventional filtering apparatus of the water recirculating network of the swimming pool, i.e. relatively far away from the water outlet. The water recirculating systems take water from the swimming pool basin through a water inlet, bring this contaminated water through a duct network to a macro-particle filter, and return this filtered water along the duct network into the swimming pool through a water outlet. Hence, it takes time for the dissolved air in the recirculated water to reach the large body of water in the swimming pool, wherein some of the dissolved air may have already begun to escape from the water carrier.